How have your designs changed over the past 40 years?
Well, like everyone I started out in the early ’70s just copying. The first amps I built for sale were based on Fender 4x10 Bassmans, and gradually I just started developing my own circuits. Now I’m not copying anything.

What products are you currently offering?
The only thing in production right now is the Little Kahuna, which is a reverberation and tremolo unit that’s all tube. I still do custom amps—one-offs and stuff. I can really only put one thing in production at a time. So I’ll do a run of a hundred of something and then do a run of a hundred of something else. I manage to make enough to at least always have a couple of amps in stock and some packed and ready to go.

The Kahuna came out in 2009?
Kind of. We did the NAMM show in 2009 and showed it. I got started actually building them at the beginning of 2010, but then I had cancer surgery so I think I only got 10 of them shipped before the surgery. It was out of circulation for a few months before I came back. Most of them have been built since late 2010.

How many have you done?
Serial numbers are up to about 70.

And how did you come up with the design?
Well there was a Big Kahuna that was fancier. It was too much trouble; I only made a couple of those. But that’s why it’s called the Little Kahuna. One day I got a sales flyer from a tube supplier and they had reissued 6BM8s. I thought, “Gee, that’d make a good reverb,” and I started tinkering with that and the tremolo. There wasn’t anything like it on the market. There were some cheesy tremolo pedals and some bad reverb units, but there wasn’t a good one in a single box.

Are you making them by yourself?
I have a company that’s making the raw cabinets for the Kahunas now, but other than that it’s all me, and I still have to finish the cabinets myself.

Zoom builds all of his amps by hand in his California workshop. Here he’s shown drilling holes in an amp chassis.

Do you use one when you play?
Yeah, not with X though—X just plays loud. The room is my reverberation. When I play rockabilly I use it, and when I do studio work I always bring it. They’re small, they’re light, they’re built like a tank—very durable.

Tell us about some of your clients.
I did all of Brian Setzer’s stuff for 18 years until he moved to Minneapolis. And the guys from the Black Crowes shoot me stuff. I’ve worked with No Doubt, Jim Lauderdale, Blind Lemon, Mike Ness, and I used to [build stuff for] Dennis Danell when he was in Social Distortion. I’ve done stuff for Jackson Browne, Richard Gere, Bruce Willis, all kinds of people. I was in Hollywood for 25 years.

I didn’t know Bruce Willis played guitar.
Bruce Willis had a band, he played harmonica, and they used to tour around Hollywood all the time. He had a bunch of Fender tweed amps I used to fix, and I fixed one of his harmonica mics.

Would you say the majority of your clients are prominent musicians or do you get amateur players as well?
Since I moved to Orange County I get a mix. I still get people from all over the country—all over the world now—but it’s a mix.

So you work one-on-one with every client?

How do you work with them to come up with something that you can both be proud of?
Well, sometimes they know what they want, and sometimes they just want something. I talk to them about what style they play and who they like, what sound they like, what records they like, where they play, and what kind of situation they’re going to use it in.

And how long does it usually take to complete one project?
To do a one-off? Probably 4 to 8 weeks—it depends how complicated it is. Usually it depends on how complicated the cabinetry is, that takes the most time. The Cowboy amp prototype I did for Gretsch took a lot of time because of the wraparound grille and all the asymmetrical parts.

And how did you get hooked up with Gretsch in the first place? Was it just because you played one of their guitars?
Yeah, well, because I was so strongly identified with that one model, the Silver Jet, which was a really unique guitar. They reissued them so they don’t seem that unusual anymore, but back in the ’70s and ’80s mine was the only one people had ever seen and they assumed that it was custom. The actual guitar became sort of an icon. When Fender got involved with Gretsch, [product manager] Joe Carducci called me up and we started working on the Billy Zoom tribute model.

When did you first start working on it?
I think 2007 was when they finally started doing it seriously. I went out to the Custom Shop a few times, and we took my old ’55 Gretsch to a Kaiser Medical Center to have it X-rayed and stuff, and they stuck little mirrors up inside of it and measured things, and then they made a couple prototypes. They sent me a prototype, then they made a couple changes to it, and put it into production.

So do you use one of the new ones or do you use your original?
I tour usually with the first prototype. I actually kind of like it. As I go to South America and Europe, when I have to fly, I usually take the standard production model. The prototype is a one-off. I don’t like to take one-of-a-kind things on airplanes.

Then why was the original prototype changed if you like it enough to tour with it?
They over-relic’d the top on the first one. The real ones don’t ever show wear on top. I think they must have gotten that coating from NASA.